Welcome to the AC Tropical Fish aquarium forum. Our aquarium forum is the place to discuss any aquarium related issue in a friendly environment. Our aquarium forum welcomes aquarists of all levels from beginners to experts. Please ask a question in the how to section of our forum or read the FAQ section if you have any questions. register to and become a part of our friendly aquarium forum community today.

Cleaning super-stubborn dried-on algae?

I have tried what I can think of, and suggestions thrown at me to clean this algae off of my acrylic tank. (And despite current looks, yes it was algae. I've scrubbed all the color off at this point.)

I've tried scrubbing with wet paper towels (using my nails, the handle of a plastic spoon, and the end of a bamboo skewer to give some stiffness to the paper towel). I've tried scrubbing with vinegar. I've tried scrubbing with H2O2. I've tried leaving vinegar-soaked paper towels on the spots, and then scrubbing. After all of that, it looks like this:

Lay the tank on it side so the side with the algae is facing down. If you have a bow front tank, your might need to wedge some towels under it to keep it stables. Soak a paper towel in pure vinegar and place the paper towel on the algae spots. Keep the paper towel on the spot for at least 24 hours and do not let it dry out. That has always worked for me to remove even tougher Coraline (marine algae) from both acrylic and glass.

Acrylic is easy to scratch so I would not suggest scrubbing the tank at all

If you take your time to do the research FIRST, you can successfully set-up and keep ANY type of aquarium with ease."Not using a quarantine tank is like playing Russian roulette. Nobody wins the game, some people just get to play longer than others." - Anthony CalfoFishless CycleCycling with FishMarine Aquarium Info [URL="http://saltwater.aquaticcommunity.com/"]

Paper towels have a grit reading of about 1500, scrub enough and they scratch. On several black automobiles I have painted they were buffed out to 4500 grit, if you dried the car with any type of paper towel it looked horrid. A cotton terry cloth has a grit rating of around 2500 to 3000 on average, try using those. 3000 is pretty well buffed, try using some non toxic acrylic aquarium polish if they remain stubborn.

I was scrubbing with paper towels, to reduce chance of scratches. However, some of the stuff really needed some elbow grease to come off.

Yup, I did read that in your first post. Soaking vinegar on the spots for about 24 hours (or more) will remove algae as well as hard water deposits. It's completely different approach which is why I suggested it. Soaking in vinegar always works a lot better than try ti scrub

If you take your time to do the research FIRST, you can successfully set-up and keep ANY type of aquarium with ease."Not using a quarantine tank is like playing Russian roulette. Nobody wins the game, some people just get to play longer than others." - Anthony CalfoFishless CycleCycling with FishMarine Aquarium Info [URL="http://saltwater.aquaticcommunity.com/"]

I had tried soaking in vinegar before, and I'm trying again with leaving it longer.

I was looking through the stickies, and I think it was green spot algae on there. One link suggested scraping with a plastic card for acrylic tanks... Did nothing. (I tested on the back of the aquarium, just to be sure.)